1. Field of the Invention
This invention relates to an aqueous dispersion of particles that mimics whole blood when applied to a reagent test strip; more specifically, an aqueous dispersion that can serve as a control solution for a photometric blood glucose measurement system.
2. Description of the Related Art
Reagent strips are quite popular for use in colorimetric reactions, in which strip color is read by a hand-held meter. Specifically, reagent strips are useful in determining the level of analytes, such as glucose, in blood. In practice, whole blood samples are placed on the reagent strip, and after reaction with components incorporated in the strips, a color change permits the determination of glucose levels. Meters, such as blood glucose meters, and reagent strips, such as glucose reagent strips, vary in accuracy and precision. It is therefore necessary to provide a monitoring agent, a "control solution", which determines whether meters and strips are providing accurate values for glucose levels. Of course, it is important to have this solution act in as close as possible a mariner to the sample, i.e., whole blood.
U.S. Pat. No. 5,187,100, issued Feb. 16, 1993 to D. P. Matzinger et al. discloses a control solution for use in a blood glucose measurement system that uses a porous membrane-based reagent strip. The system is adapted to measure concentrations of glucose in whole blood in the presence of optically visible hemoglobin. The control solution comprises a dispersion of a non-water soluble polymer in water, coupled with controlled levels of glucose. Polyvinyl acetate is a preferred polymer.
The control solution of Matzinger et al. is adapted for use in ONE-TOUCH.RTM. blood glucose meters, which measure reflectance from a reagent strip at 635 nm and 700 nm. It is not suitable for use in the newer SURESTEP.TM. blood glucose meters, which measure strip reflectance at 660 nm and 940 mm.